The fourth phone in my Vtech 6.0, model CS6328-4. will not give me a dial tone. When I place it on the base to charge, it prints "out of range or no pwr at base". I also cannot get the handset registered to the base. Other handsets will work in the room on the base in question. I traded the phone in for a new one, but had the same problem. How do I fix it?

SOURCE: Handset not registering with base

You could try to clear all the memory from the base unit and start again!!!
Instructions to clear phone (Uniden 8855).
1. Go to your base unit.
2. Put your flip phone in the cradle.
3. Press down and hold down (AT ALL TIMES) the end (find hs) button.
4. Whilst holding down this button, take the power plug out of the wall.
5. Whilst still holding down the end (find hs) button, plug the power back in.
6. When you hear a beep from the base unit system.
7. Let go of the end (find hs) button.
8. Your phone memory should be cleared now and you are ready to repeat the process of registering your base and additional handsets.

SOURCE: Uniden Cordless handset

we purchased the uninden 3 pack bundle they worked fine when installed now one handset will light up but the screen comes up blank and the handset won't work also if this can be corrected i would like to know how to purchase one extra hand set and charger

SOURCE: No Dial Tone 1 Handset

I think I have the same phone. You have to put the handset with no dialtone in the main charger for about 30 seconds to reset it to the base.

SOURCE: VT2461 ADDITIONAL HANDSET PROBLEM

I can vouch for the second solution. It worked perfectly on my 2461 with two extensions. Even the vTech website was not able to provide a solution.

SOURCE: My vtech 5825 screen says NOT REGISTERED and does not work

Place the handset in the charger and press find handset for 4 seconds.This will register the handset. do the same for other handsets.